DownloadRequester now throws an exception if request is invalid

2 files changed, 87 insertions, 20 deletions

diff --git a/src/de/danoeh/antennapod/storage/DownloadRequestException.java b/src/de/danoeh/antennapod/storage/DownloadRequestException.java
new file mode 100644
index 000000000..0ef766e58
--- /dev/null
+++ b/src/de/danoeh/antennapod/storage/DownloadRequestException.java
@@ -0,0 +1,25 @@
+package de.danoeh.antennapod.storage;
+
+/**
+ * Thrown by the DownloadRequester if a download request contains invalid data
+ * or something went wrong while processing the request.
+ */
+public class DownloadRequestException extends Exception {
+
+	public DownloadRequestException() {
+		super();
+	}
+
+	public DownloadRequestException(String detailMessage, Throwable throwable) {
+		super(detailMessage, throwable);
+	}
+
+	public DownloadRequestException(String detailMessage) {
+		super(detailMessage);
+	}
+
+	public DownloadRequestException(Throwable throwable) {
+		super(throwable);
+	}
+
+}
diff --git a/src/de/danoeh/antennapod/storage/DownloadRequester.java b/src/de/danoeh/antennapod/storage/DownloadRequester.java
index 13c8f58d0..928b923fd 100644
--- a/src/de/danoeh/antennapod/storage/DownloadRequester.java
+++ b/src/de/danoeh/antennapod/storage/DownloadRequester.java
@@ -60,7 +60,7 @@ public class DownloadRequester {
 
 			DownloadService.Request request = new DownloadService.Request(
 					item.getFile_url(), item.getDownload_url());
-			
+
 			if (!DownloadService.isRunning) {
 				Intent launchIntent = new Intent(context, DownloadService.class);
 				launchIntent.putExtra(DownloadService.EXTRA_REQUEST, request);
@@ -78,20 +78,44 @@ public class DownloadRequester {
 		}
 	}
 
-	public void downloadFeed(Context context, Feed feed) {
-		download(context, feed, new File(getFeedfilePath(context),
-				getFeedfileName(feed)));
+	public void downloadFeed(Context context, Feed feed)
+			throws DownloadRequestException {
+		if (feedFileValid(feed)) {
+			download(context, feed, new File(getFeedfilePath(context),
+					getFeedfileName(feed)));
+		}
+	}
+
+	public void downloadImage(Context context, FeedImage image)
+			throws DownloadRequestException {
+		if (feedFileValid(image)) {
+			download(context, image, new File(getImagefilePath(context),
+					getImagefileName(image)));
+		}
 	}
 
-	public void downloadImage(Context context, FeedImage image) {
-		download(context, image, new File(getImagefilePath(context),
-				getImagefileName(image)));
+	public void downloadMedia(Context context, FeedMedia feedmedia) throws DownloadRequestException {
+		if (feedFileValid(feedmedia)) {
+			download(context, feedmedia,
+					new File(getMediafilePath(context, feedmedia),
+							getMediafilename(feedmedia)));
+		}
 	}
 
-	public void downloadMedia(Context context, FeedMedia feedmedia) {
-		download(context, feedmedia,
-				new File(getMediafilePath(context, feedmedia),
-						getMediafilename(feedmedia)));
+	/**
+	 * Throws a DownloadRequestException if the feedfile or the download url of
+	 * the feedfile is null.
+	 * 
+	 * @throws DownloadRequestException
+	 */
+	private boolean feedFileValid(FeedFile f) throws DownloadRequestException {
+		if (f == null) {
+			throw new DownloadRequestException("Feedfile was null");
+		} else if (f.getDownload_url() == null) {
+			throw new DownloadRequestException("File has no download URL");
+		} else {
+			return true;
+		}
 	}
 
 	/**
@@ -158,7 +182,8 @@ public class DownloadRequester {
 	/** Remove an object from the downloads-list of the requester. */
 	public void removeDownload(FeedFile f) {
 		if (downloads.remove(f.getDownload_url()) == null) {
-			Log.e(TAG, "Could not remove object with url " + f.getDownload_url());
+			Log.e(TAG,
+					"Could not remove object with url " + f.getDownload_url());
 		}
 	}
 
@@ -167,29 +192,46 @@ public class DownloadRequester {
 		return downloads.size();
 	}
 
-	public String getFeedfilePath(Context context) {
-		return context.getExternalFilesDir(FEED_DOWNLOADPATH).toString() + "/";
+	public String getFeedfilePath(Context context)
+			throws DownloadRequestException {
+		return getExternalFilesDirOrThrowException(context, FEED_DOWNLOADPATH)
+				.toString() + "/";
 	}
 
 	public String getFeedfileName(Feed feed) {
 		return "feed-" + NumberGenerator.generateLong(feed.getDownload_url());
 	}
 
-	public String getImagefilePath(Context context) {
-		return context.getExternalFilesDir(IMAGE_DOWNLOADPATH).toString() + "/";
+	public String getImagefilePath(Context context)
+			throws DownloadRequestException {
+		return getExternalFilesDirOrThrowException(context, IMAGE_DOWNLOADPATH)
+				.toString() + "/";
 	}
 
 	public String getImagefileName(FeedImage image) {
 		return "image-" + NumberGenerator.generateLong(image.getDownload_url());
 	}
 
-	public String getMediafilePath(Context context, FeedMedia media) {
-		File externalStorage = context.getExternalFilesDir(MEDIA_DOWNLOADPATH
-				+ NumberGenerator.generateLong(media.getItem().getFeed()
-						.getTitle()) + "/");
+	public String getMediafilePath(Context context, FeedMedia media)
+			throws DownloadRequestException {
+		File externalStorage = getExternalFilesDirOrThrowException(
+				context,
+				MEDIA_DOWNLOADPATH
+						+ NumberGenerator.generateLong(media.getItem()
+								.getFeed().getTitle()) + "/");
 		return externalStorage.toString();
 	}
 
+	private File getExternalFilesDirOrThrowException(Context context,
+			String type) throws DownloadRequestException {
+		File result = context.getExternalFilesDir(type);
+		if (result == null) {
+			throw new DownloadRequestException(
+					"Failed to access external storage");
+		}
+		return result;
+	}
+
 	public String getMediafilename(FeedMedia media) {
 		return URLUtil.guessFileName(media.getDownload_url(), null,
 				media.getMime_type());